# Session handoff — 2026-05-15 (10) Tenth handover. This session executed **ADR-0024 Phase F (full) steps 1–4** on top of handoff-9: the walker now drives highlighting, usage rendering, and the schema-list / completion ident-source vocabulary. `dsl::lexer`, `dsl::keyword`, `dsl::ident_slot`, and `dsl::usage` are deleted; their catalog wrappers (`parse.token.keyword.*` and `parse.token.punct.*`) are deleted too. Four commits in clean incremental steps. What did NOT land — and what the next session picks up — is captured below. ## State at handoff **Branch:** `main`. Working tree clean. **Local HEAD is `fa994cf`**, ahead of `origin/main` by five commits (user pushes asynchronously). Commits since handoff-9's baseline (`b3d3bdf`): ``` 7bdd398 ADR-0024 Phase F (full) step 1: walker-driven highlighting a41400e ADR-0024 Phase F (full) step 2: usage via CommandNode.usage_ids 266b4c2 ADR-0024 Phase F (full) step 3: delete legacy parser modules fa994cf ADR-0024 Phase F (full) step 4: catalog token-keyword cleanup ``` **Tests:** **806 passing, 0 failing, 1 ignored** (was 844 at handoff-9; the net drop reflects the removal of legacy-module tests — ~45 tests in `dsl::lexer`, `dsl::keyword`, `dsl::ident_slot`, `dsl::usage` — minus 16 new walker highlight tests). The ignored test is still the same `\`\`\`ignore` doc-test in `src/friendly/mod.rs`. **Clippy:** clean with `nursery` lints + `-D warnings`. **Cargo.toml:** unchanged (chumsky was already gone in handoff-9). ## What shipped this session ### Step 1 — Walker-driven highlighting (commit 7bdd398) `input_render::base_runs` no longer calls `lex()`. The new `walker::highlight::highlight_runs(source) -> Vec` combines walker `per_byte_class` output (for matched portions) with a byte-shape fallback (over `lex_helpers`) for trailing junk / unknown-command words / unterminated strings. The fallback handles UTF-8 codepoints byte-exact and produces an `Error` class for unrecognised bytes — preserves the `$` → `tok_error` behaviour from the lexer-driven path. `Theme::highlight_class_color(HighlightClass) -> Color` replaces `Theme::token_color(&TokenKind)`. The renderer reads `HighlightClass` directly off `ByteClass`. `#[allow(dead_code)]` is off `HighlightClass` and `WalkResult::per_byte_class` — they are part of the production path now. 16 new walker-highlight tests pin the byte-class output for walks, fallbacks, multi-byte UTF-8, and the trailing-token case. ### Step 2 — Usage rendering via `CommandNode.usage_ids` (commit a41400e) `CommandNode.usage_id: Option<&'static str>` becomes `usage_ids: &'static [&'static str]`. Multi-form families (`drop`, `add`, `show`) carry every variant — the legacy `dsl::usage::matched_entry` returned multi-key Vec for those families and the walker registry now matches that. App-lifecycle commands had been pointed at non-existent `parse.usage.app.*` catalog keys (an unnoticed bug introduced in handoff-9 because the field was unused at the time); they now point at the real catalog entries. Two new helpers in `dsl::grammar`: - `usage_keys_for_input(source) -> Option<(entry_word_text, usage_ids)>` resolves the input's first identifier-shape token to a CommandNode and returns its usage_ids list. Used by `app::render_usage_block` (parse-error rendering) and `input_render::ambient_hint` (live hint panel). - `entry_words_alphabetised() -> Vec<&'static str>` replaces `dsl::usage::entry_keywords_alphabetised`. `dsl::usage` is deleted entirely. The "available commands:" fallback in `render_usage_block` formats entry words as `` `` `` directly (replacing the `parse.token.keyword.*` catalog lookup; equivalent rendering). `parse_command` and `parse_tokens` slim down: no pre-lex pass; the walker scans source bytes directly. `parse_tokens` (which had been kept `pub` "for future I3/I4 work") is folded into `parse_command`. ### Step 3 — Legacy module deletion (commit 266b4c2) Deleted: `src/dsl/lexer.rs`, `src/dsl/keyword.rs`, `src/dsl/ident_slot.rs`. `IdentSource` (`dsl::grammar`) absorbs the schema-list / expected-label / round-trip semantics that previously lived on `IdentSlot`. The walker's `Expectation::Ident { source }` and the schema-lookup request on the database worker now share one enum: - `IdentSource::Tables`, `Columns`, `Relationships` are the schema-listable sources (`completes_from_schema() == true`). - `IdentSource::NewName` is the user-invents kind. - `IdentSource::Types` is the closed-set source on column-type slots — does not query the schema; the walker's content validator handles type-name validity. - `IdentSource::Free` is the catch-all branch in `mode` / `messages` value slots. `SchemaCache::for_slot(IdentSlot)` becomes `for_source(IdentSource)`; `Database::list_names_for` and the `Request::ListNamesFor` worker variant take `IdentSource`. `InvalidIdent.slot: IdentSlot` becomes `InvalidIdent.source: IdentSource`. Completion's keyword filter (was `Keyword::from_word`) becomes "backticked items whose payload is all ASCII alphabetic" — punct and digit literals (`,`, `1`) still surface through their own candidate sources (composite-literal, flag, schema-ident). The alphabetic filter excludes them from the keyword bucket. `friendly::keys::tests::keyword_and_punct_have_complete_token_vocabulary` is dropped (cross-checked enum vs. catalog completeness; both enums are gone). ### Step 4 — Catalog token-keyword cleanup (commit fa994cf) Dropped the 47 `parse.token.keyword.*` and 6 `parse.token.punct.*` catalog entries (yaml + keys.rs). Nothing consumes them: keyword wording is produced verbatim by `format!("\`{word}\`")`, sourced from grammar-tree Word literals. Punct wording surfaces the same way via `Expectation::Punct(ch)`. Structural-class labels (`parse.token.identifier`, `.number`, `.string_literal`, `.flag`, `.end_of_input`) and lex-error wordings (`parse.token.error.{bad_flag,unknown_char, unterminated_string}`) stay. None of these are derivable from the grammar tree. `keys_validate_against_catalog` continues to enforce catalog ↔ `KEYS_AND_PLACEHOLDERS` bidirectional coverage on the trimmed set. ## DEFERRED — work the next session needs to pick up Items grouped by priority. Roughly in order of decreasing payoff. ### 1. Walker-driven completion (Phase F full step 5) The current completion path: ``` input → parse_command → ParseError::Invalid::expected: Vec → completion.rs parses each string back to IdentSource via from_expected_label ``` This works but loses information. The walker knows the full `IdentSource` of every expected slot, the `role` of every slot (e.g. `parent_table` vs `child_table`), the `skipped` expectations from any Optional that didn't engage, the cursor's full `MatchedPath` so far — and the bridge throws all of that away to render strings. **Migration**: add a `expected_walker: Vec` field on `ParseError::Invalid` (additive, doesn't break consumers yet). Or a new `walker::candidates_at(input, cursor) -> WalkResult` API. Update `completion.rs::candidates_at_cursor` to read `Expectation::Ident { source, role }` directly. The walker already supports `WalkBound::Position(cursor)` (the variant exists in `outcome.rs`); no caller passes it today. Adopting it lets completion see the cursor's full context. **Estimated cost:** one session. Smaller than the steps that landed this round. ### 2. Phase D (full): schema-aware value typing Unchanged from handoff-9 §2 — same scope, same blockers. Specifically: - `WalkContext::current_table`, `current_table_columns`, `current_column` are declared but unwritten. - `Node::DynamicSubgrammar(fn(&WalkContext) -> Node)` is declared; the walker driver returns `Failed { expected: vec![] }` on that branch (deliberate — catches mis-declared grammar). Walker dispatch needs implementing per ADR-0024 §sub-grammars (`Box::leak` per walk, or per-walk arena). - `SchemaCache` carries flat `columns: Vec`; per-table column-with-type info needs adding. - `Ident { source: Tables }` has no `writes_table: bool` flag; walker can't populate `current_table` on match. - Typed value slots (`int_slot`, `decimal_slot`, …) are not declared. **The user UX win this unlocks:** typed slots reject mis-shaped input at parse time with localised wording ("Type a date as 'YYYY-MM-DD'") instead of bind-time errors; completion narrows per column type. Round-5 "value-literal hint by column type" becomes type-specific. **Sequence to implement** (from handoff-9 §2): 1. Plumb a `SchemaCache` reference into `parse_command`; thread through `WalkContext::new(schema)`. 2. Implement `Node::DynamicSubgrammar` walker dispatch. 3. Add `writes_table: bool` (or analogous) to `Node::Ident` and have the walker populate `WalkContext::current_table` + `current_table_columns` from the schema cache when it matches. 4. Implement typed value slots — content validators for each `Type`. 5. Wire `column_value_list` as a `DynamicSubgrammar` that reads `current_table_columns` and emits a `Seq` of typed slots separated by commas. 6. Update `insert` shape to use `column_value_list`. 7. Update `update` / `delete` to use the per-column value slot based on `current_column`. **Side effect to watch:** `parse_command` becomes schema-dependent. Tests that exercised parse in isolation without a schema will need to either pass a schema cache or fall back to the type-unaware path (Option<&SchemaCache>). **Estimated cost:** 1–2 sessions, as last session estimated. ### 3. HintMode annotations on grammar nodes `HintMode::{Default | ForceProse | ProseOnly | SuppressProse}` is declared in `grammar/mod.rs`. Every `CommandNode` and every `Node::Ident` sets it to `None`. The current ad-hoc hint cases in `input_render.rs::ambient_hint` (`value_literal_hint_at_cursor`, `typing_name_at_cursor`, `invalid_ident_at_cursor`) still drive the hint panel. ADR-0024 §HintMode-per-node says these migrate to node-attached annotations during Phase D. They didn't (handoff-9 confirmed, this session didn't move them either). To do once Phase D lands: annotate the value-literal slots with `HintMode::ProseOnly("value_literal_format_hint")`, NewName slots with the typing-name prose, and have the hint resolver dispatch on the walker's per-expected-node mode. The current stopgap `value_literal_hint_at_cursor` becomes "narrow to the column's type" instead of generic. ### 4. Ranker hook (declared in ADR-0024, not implemented) ADR-0024 §ranker-layer specifies a `Ranker` function type between the walker's raw candidates and the hint-panel renderer. Default is `identity_ranker` (declaration-order preserved). **Status: not declared anywhere in code.** Future plug-in point for frequency-based ranking, content-aware priors, recency. Non-blocking. ### 5. Differential-test scaffolding wasn't built (carried from handoff-9) ADR-0024 §test-discipline §3 specified a "differential check during the migration window" — a test helper running both parsers against the input corpus, asserting identical `Command` output. Since chumsky is gone (removed in Phase F minimal), running the differential retroactively would require reconstructing the chumsky path from git history. Not worth it — the hand-curated `dsl::walker::tests` (53 tests) and the existing integration test suite serve the same regression-net role. ### 6. `WalkContext` writes during walk — design exists, not implemented Carried from handoff-9 §12. `Ident { source: Tables, writes_table: true }` semantics: when the ident matches, the walker writes `current_table` to context. Subsequent dynamic sub-grammars read it. Today no `Ident` node has a `writes_table` field. Adding it is part of Phase D §3 above. ### 7. `CommandNode.help_id` not consumed Carried from handoff-9 §13. Every `CommandNode` declares `help_id: Option<&'static str>` pointing into the catalog. **No code reads it.** Wiring up in-app help to read this field (replacing hand-curated `help.in_app_body` lookups) is future work — not blocking, not user-facing. ### 8. Dead `parse.token.*` catalog entries The five structural-class entries (`parse.token.identifier/number/string_literal/flag/end_of_input`) and three lex-error entries (`parse.token.error.{bad_flag,unknown_char,unterminated_string}`) remain in the catalog after step 4. They are unreferenced by production code today — the walker classifies bytes by shape for highlighting and emits structural / validation errors with catalog keys directly (e.g., `mode.unknown`). Conservative call this session: leave them in. They cost nothing, and re-introducing them would be cheap if a future need arises. If you decide they're truly dead, drop the entries from `friendly/strings/en-US.yaml` and the corresponding declarations from `friendly/keys.rs`. ## Sharp edges (carried from handoff-9 with updates) - **Optional backtracking on partial-match** is intentional — matches chumsky's `or_not` semantics. See handoff-9 for the asymmetry between content (no rollback) and structural (roll back). Unchanged. - **Walker's `Choice` is strictly greedy.** Unchanged. - **`Ident { source: Tables/Columns/Relationships }` does NOT validate against the schema at parse time.** Still shape-only. Phase D §3 unlocks schema-aware parse. - **`Literal(&'static str)` matches verbatim bytes with a word-boundary lookahead.** Unchanged. - **`AST builder` failures surface as `WalkOutcome::ValidationFailed`** with `at_eof = true`. Unchanged. - **`unknown_command_error` is the sole catch-all** for inputs whose first identifier-shape token isn't a registered entry word. Now read from `dsl::grammar::entry_words_alphabetised()` (was `usage::entry_keywords_alphabetised`). - **`q` quit alias remains gone.** Native walker alias support still works: adding `q` back is `aliases: &["q"]` on `QUIT.entry`. Walker matches either; completion surfaces only the primary. - **Path-bearing UX (replay / import / export):** unchanged from handoff-9 — paths with spaces use the quoted form. - **Highlight fallback semantics (new this session):** for inputs the walker doesn't engage on (no registered entry word, e.g., `frobulate widgets`) the byte-shape scanner classifies each shape as Identifier, Number, String, Flag, Punct, or Error. The user sees normal token colouring on the unknown command before the `[error]` line fires on submit. This matches the pre-walker behaviour. - **Stopgap `value_literal_hint_at_cursor` continues to fire** for every value-literal slot regardless of column type. Same wording as handoff-9. Replaced once Phase D §4 typed slots land. ## ADR index (delta vs. handoff-9) ``` 0019 Friendly error layer and i18n catalog — parse.token.keyword/punct.* entries collapsed (Phase F) 0020 Tokenization layer for the DSL parser — superseded; dsl::lexer module deleted (Phase F) 0021 Parser-as-source-of-truth for H1a — partial: usage info reads from CommandNode.usage_ids; help_id wiring deferred (handoff-10 §7) 0022 Ambient typing assistance — completion still reads ParseError-string expected; walker-direct path pending (handoff-10 §1) 0024 Unified grammar tree: execution plan (ACCEPTED) — A through F full steps 1–4 landed. F step 5 (walker-direct completion) + D full deferred. ``` ## Repository layout (delta vs. handoff-9) Files deleted: ``` src/dsl/lexer.rs (598 lines) src/dsl/keyword.rs (311 lines) src/dsl/ident_slot.rs (140 lines) src/dsl/usage.rs (318 lines) ``` Files added: ``` src/dsl/walker/highlight.rs (319 lines) docs/handoff/20260515-handoff-10.md (this file) ``` Files significantly modified: ``` src/dsl/grammar/mod.rs — usage_ids, usage_keys_for_input, entry_words_alphabetised, IdentSource expanded with helpers src/dsl/grammar/app.rs — usage_ids tuples (corrected catalog keys) src/dsl/grammar/ddl.rs — usage_ids tuples (drop/add family) src/dsl/grammar/data.rs — usage_ids tuples (show family) src/dsl/parser.rs — slimmed; chumsky-side parse_tokens folded in src/dsl/walker/mod.rs — re-export highlight_runs src/dsl/walker/outcome.rs — ByteClass / WalkResult fields no longer #[allow(dead_code)] src/dsl/mod.rs — removed legacy module declarations src/app.rs — render_usage_block via walker registry src/input_render.rs — base_runs via walker::highlight_runs; ambient_hint via usage_keys_for_input src/completion.rs — IdentSource throughout; keyword filter via ASCII-alphabetic check src/db.rs — Request::ListNamesFor takes IdentSource src/runtime.rs — refresh_schema_cache uses IdentSource src/theme.rs — highlight_class_color; token_color removed src/friendly/keys.rs — parse.token.keyword/punct.* dropped src/friendly/strings/en-US.yaml — same drops ``` ## How to take over 1. **Read this file.** 2. **Read `CLAUDE.md`** for the working-style rules. 3. **Read handoff-9** (`20260515-handoff-9.md`) for context on the ADR-0024 phases that landed in the prior session and any carry-over sharp edges. 4. **Read ADR-0024** for the design intent. F-step-5 (walker-direct completion) and Phase D full are the unfinished work; their sketches live in §migration of that ADR. 5. **Skim `src/dsl/grammar/mod.rs`** — the Node / Word / CommandNode / REGISTRY / IdentSource / HintMode contract. 6. **Skim `src/dsl/walker/mod.rs` + `walker/highlight.rs`** — the walk() entry, bridge logic, and the new highlight-runs API. 7. **Run `cargo test`** — should report 806 passing, 0 failing, 1 ignored. 8. **Run `cargo clippy --all-targets -- -D warnings`** — clean. 9. **Pick a deferred item from §1–§4** and start. §1 (walker- driven completion) is the natural next move; it removes the string round-trip and unlocks richer hints. §2 (Phase D full) is the largest item and the biggest user-visible payoff. ### End-to-end smoke (current state) Same as handoff-9's smoke; nothing in user-visible behaviour changed this session. All four steps were silent refactors of internal machinery — same parse, same dispatch, same wording on errors, same colours on tokens. The catalog cleanup removed unused YAML entries; no string the user sees was sourced from them.